Racemic phenylalanine is a compound in which L-phenylalanine and D-phenylalanine are mixed in equal amounts. Their physical and chemical properties are basically the same, but their optical activity is opposite to each other. Therefore, it is difficult to separate the racemate into phenylalanine with a single configuration by general physical methods, and a special method must be used for separation. Using 3,5-dinitrobenzoyl substituted β-cyclodextrin as the stationary phase, chiral thin-layer chromatography was used to resolve D, L-amino acids. It was found that phenylalanine was due to the existence of the benzene ring structure The strong interaction with the chiral stationary phase makes the racemic phenylalanine have different physical properties, so a better resolution effect is obtained. However, the resolution agent used in this method is expensive, consumes a lot, and the resolution efficiency is not high, so it is difficult to prepare for large-scale production and use. Penicillin acylase was immobilized, and then the racemic phenylalanine derivative N-phenylacetyl-D, L-phenylalanine was resolved to obtain the crude product N-phenylacetyl-D-phenylalanine, which was purified by water The protection group was removed, and then the cationic resin exchange desalting treatment was used to obtain D-phenylalanine with an optical purity of 91.4% and a yield of 67%. This method also has the disadvantages of low efficiency, high energy consumption, low yield, and low optical purity of the product. There are also related literature reports that racemic phenylalanine is resolved with chemical reagent dioxaphosphorinane compounds, but the resolution rate is less than 36%.